This is a substitute application for application Ser. No. 904,818 filed May 11, 1978, now abandoned.
Generally speaking, the present invention pertains to a timing mechanism wherein a cam means is rotatably driven by power drive means through an improved intermittent drive means, the improved intermittent drive means comprising first and second ratchet means coupled to the cam means, first and second drive pawls coupled to the power drive means engaging the first and second ratchet means respectively, and a no back clutch operably associated with the cam means preventing reversal thereof during its engagement.
The present invention pertains to timing mechanisms and more particularly to a drive and clutch means for intermittently rotating its cam means.
Timing mechanisms find great use in applicances such as washers, dryers, and dishwashers. Such mechanisms usually include a camstack, the cams of which engage electrical switches to open and close them in accordance with a program determined by the cams, a power drive means, and a means coupling the power drive means to the camstack. In most cases, the coupling means is an intermittent drive means or escapement.
As such appliances become more complicated due to the different materials being washed and dried, the programs and thus the timing mechanisms become more complicated. It thus becomes an ever increasing problem to find ways and means to provide more programs with more precise control of events, and usually within a limited space.
Another problem associated with such mechanisms is that of the intermittent drive means or the escapement itself. Usually the intermittent drive means include rathet and pawl arrangements wherein a back up or no back pawl prevents or at least limits the back lash of the camstack as it is intermittently advanced by the drive pawl. While in most cases the use of a no back pawl is satisfactory, in most cases there is undesirable reversing capability due to the "lag" in the back up pawl engaging a tooth.